Differences Between Squamous Intraepithelial Lesions of the Vulva and the Cervix.

The Lower Anogenital Squamous Terminology project and subsequent publication have grouped preinvasive human papillomavirus-associated squamous intraepithelial lesions of the lower genital tract and adjacent skin as a single entity. We are concerned that as a result of this grouping, some of the clinically relevant differences may not be taken into consideration. We describe differences between high-grade squamous intraepithelial lesion of the vulva and cervix (vulvar intraepithelial neoplasia and cervical intraepithelial neoplasia), in embryology (arising from ectoderm vs mesoderm), clinical presentations (symptoms or signs due to many vulvar lesions vs abnormal cytology), examination techniques and diagnosis (clinical examination of potentially widely involved areas vs colposcopy of the transformation zone), natural history, management, and follow-up requirements (long-term clinical assessment vs cytology and human papillomavirus testing). We believe that failure to understand these important differences will lead to errors in management.